Table 2.
Quality assessment of case-control studies included by NOS
| Study, year | Selection | Comparability | Exposure | Overall stars | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Is the case definition adequate? | Representative of the cases | Selection of controls | Definition of controls | Control for important factors | Control for any additional factor | Ascertainment of exposure | Same method of ascertainment for cases and controls | Nonresponse rate | ||
| Antonelli 2002 [14] | ★ | ★ | ★ | ★ | ★ | ★ | ★ | ★ | - | 8 |
| Principi 2004 [17] | ★ | ★ | - | ★ | ★ | - | ★ | - | - | 5 |
| Antonelli 2004 [20] | ★ | ★ | - | ★ | ★ | - | ★ | - | - | 5 |
| Tonnelier 2003 [33] | ★ | ★ | - | ★ | ★ | ★ | ★ | - | - | 6 |
| Rocco 2004 [34] | ★ | ★ | - | ★ | ★ | ★ | ★ | - | - | 6 |
NOS Newcastle-Ottawa scale; ★ the quality met the criterion of this specific item, - the item was not qualified to be awarded a star